JP4005111B2 - Method and apparatus for measuring sound pressure level difference between rooms - Google Patents

Description

  The present invention relates to an inter-room sound pressure level difference measuring method and apparatus for examining the sound insulation performance of a room in a detached house or an apartment house.

Conventionally, the measurement of the inter-room sound pressure level difference is performed by a method stipulated in a certain industrial standard defined by law. FIG. 7 is a diagram showing a configuration and a measuring method of an inter-room sound pressure level difference measuring apparatus used in the conventional measurement, and the inter-room sound pressure level difference measuring apparatus is installed in the sound source room A. A sound source device 24 including a sound source generator 21 for generating noise used for measuring a sound pressure level, a power amplifier 22 and a speaker 23, and a sound receiving room B different from the sound source room A and the sound source room A. And a sound receiving device 26 including two microphones 25a and 25b for collecting sound pressure signals in the sound source chamber A and the sound receiving chamber B. The sound receiving device 26 includes a changeover switch 27 for switching input of sound pressure signals collected by the microphones 25a and 25b, an octave band filter 28 which is a filter for band-limiting the input sound pressure signal, and a level indicator 29. A sound level meter 30 that detects a sound pressure level (dB) of the sound pressure signal band-limited by the octave band filter 28 and displays the sound pressure level (dB) in an analog manner on the level indicator 29; It has.
As shown in FIG. 8, the sound generator 21 has a fundamental frequency of 125 Hz, and six types of frequencies whose frequency increases by one octave (f ₁ = 125 Hz, f ₂ = 250 Hz, f ₃ = 500 Hz, f ₄ = 1000 Hz). , f ₅ = 2000 Hz, f ₆ = 4000 Hz), each generating noise with a width of one octave. When measuring the sound pressure level difference between rooms, the above six types of noise are generated one by one. Let The noise generated by the sound source generator 21 is amplified by the power amplifier 22 and radiated from the speaker 23 into the sound source room A. Note that the speaker 23 is placed on the floor at the corner of the sound source room A so that the sound pressure level in the sound source room A becomes substantially constant and the noise does not directly enter the sound receiving room B. It is installed at a height of approximately 1.2 to 1.5 m.

Next, a method for measuring the inter-room sound pressure level difference will be described. As shown in FIG. 7, five locations (A _{1 to} A ₅ ) in the sound source chamber A and five locations (A _{1 to} A ₅ ) in the sound receiving chamber B (as shown in FIG. 7) are collected by the microphones 25a and 25b. B ₁ is a total of 10 points of ~B _5). In the figure, the workers S _{1 to} S ₄ who perform the measurement are omitted.
First, in the sound source room A, the operator S ₁ operates the sound source device 24 to generate noise having a bandwidth of one octave with a center frequency of f ₁ = 125 Hz from the speaker 23, and the operator S ₂ the measurement point a ₁ of chamber a by setting the microphone 25a for collecting sound pressure signal at the measurement point a _1. On the other hand, in the receiving room B, and the operator S ₃ sets a microphone 25b to the measurement point B _1, collecting the sound pressure signal at the measurement point B _1. In addition, the operator S ₄ operates the sound receiving device 26 to adjust the center frequency of the octave band filter 28 to f ₁ = 125 Hz, connects the changeover switch 27 to the microphone 25 a side, and collects the measurement points collected by the microphone 25 a. The sound pressure signal at A ₁ is input to the sound level meter 30, and the sound pressure level L _A11 (dB) at the measurement point A ₁ detected by the sound level meter 30 is read from the level indicator 29 and recorded on the recording sheet. Then, the operator S _4, it switches the input signal to noise meter 30 by operating the change-over switch 27, the noise sound pressure level L _B11 of the sound pressure signal at the measurement point B ₁ taken by the microphone 25b (dB) A total of 30 level indicators 29 are read and recorded on recording paper. In the following, L _Aij (dB) represents a sound pressure level at which the measurement point is A _i and the center frequency of noise is f _j , and L _Bij (dB) is the measurement point at B _i and the noise level. Let us denote a sound pressure level whose center frequency is f _j .
Next, the worker S ₂ and the worker S _{3 place the} microphones 25 a and 25 b at the measurement points A ₂ and B ₂ (see FIG. 7) as the next measurement points in the sound source room A and the sound receiving room B, respectively. The sound pressure signals in the sound source chamber A and the sound receiving chamber B are measured at the measurement points A ₂ and B ₂ . The operator S ₄ uses the sound pressure level L _A21 (dB) of the sound pressure signal at the measurement point A ₂ collected by the microphone 25a and the sound pressure level L _B21 of the sound pressure signal at the measurement point B ₂ collected by the microphone 25b. (DB) is read from the level indicator 29 of the sound level meter 30 and recorded on a recording sheet. As described above, the workers S ₂ and S ₃ set the microphones 25a and 25b at the measurement points A _{1 to} A ₅ and the measurement points B _{1 to} B ₅ , respectively, and collect sound pressure signals at the respective measurement points. The operator S ₄ detects and records the sound pressure levels L _A11 (dB) to L _A51 (dB) and the sound pressure levels L _B11 (dB) to L _B51 (dB) of the sound pressure signal on the recording paper.
When the measurement of the sound pressure level with respect to the noise having the center frequency f ₁ = 125 Hz is completed, the operator S ₁ operates the sound source device 24 to set the center frequency of the noise to be generated to f ₂ = 250 Hz. Workers S ₂ and S ₃ collect sound pressure signals at the respective measurement points (A _{1 to} A ₅ and B _{1 to} B ₅ ) by the same work as described above, and worker S ₄ Sound pressure levels L _A12 (dB) to L _A52 (dB) and sound pressure levels L _B12 (dB) to L _B52 (at the respective measurement points (A _{1 to} A ₅ and B _{1 to} B ₅ ) dB) is detected and recorded on the recording paper. In this way, the sound pressure levels L _Aij (dB) and L _Bij (dB) at the measurement points A _{1 to} A ₅ and the measurement points B _{1 to} B ₅ are detected and recorded on the recording paper or the like for the six types of frequencies. .
Note that the sound pressure level L _ij (dB) is measured at the measurement points A _{1 to} A ₅ in the sound source chamber A and then measured at the measurement points B _{1 to} B ₅ in the sound receiving chamber B. May be. In order to simplify the measurement, two sound receiving devices 26 in which a microphone is connected to a sound level meter having an octave band filter and a level indicator are prepared, and in the sound source room A and the sound receiving room B, In many cases, the sound pressure level L _ij (dB) is measured. In this case, the levels of the two sound receiving devices 26 are adjusted in advance.

When the difference between the maximum and minimum values of the sound pressure levels L _Aij (dB) and L _Bij (dB) at each measurement point in the sound source room A and the sound receiving room B is 10 dB or less, The sound pressure level difference is obtained as the average sound pressure level difference between rooms. If the difference between the maximum value and the minimum value exceeds 10 dB, the sound pressure level difference between specific locations is calculated without calculating the average sound pressure level difference between rooms. Since there is no relation to the above problem, only the case of obtaining the inter-room average sound pressure level difference will be described.
First, the sound pressure levels L _Aij (dB) and L _Bij (dB) are converted into sound pressure effective values P _Aij and P _Bij using the following equation (1), and then each of the sound pressure levels L _Aij (dB) and L _Bij (dB) is expressed by the following equation (2). Average values P _Aj and P _Bj of sound pressure effective values for the frequencies (f _{1 to} f ₆ ) are calculated. In the following formulas, the suffixes A and B indicating the sound source room A or the sound receiving room B are omitted.
P ² _ij = P ² ₀ log ₁₀ ⁻¹ (L _ij / 10) = P ² ₀ · 10 ^{(Lij / 10)} (1)
P ² _j = (1 / n) · ΣP ² _ij
= (P ² ₀ / n) · Σ10 ^{(Lij / 10)} (2)
However, P ₀ is the reference sound pressure, P ₀ = 20 μPa, and Σ represents the sum of the measurement points A _i or B _i (i = 1 to n). Here, n = 5.
Power Average L _j of the sound pressure level of the frequency f _j is represented by equation (3) below using the average value P _j of the sound pressure effective value of the equation (2).
L _j = ₁₀ log ₁₀ (P ² _j / P ² ₀ )
= ₁₀ log ₁₀ (Σ10 ^{(Lij / 10)} ) − ₁₀ log ₁₀ n (3)
Thus, expressed chamber between average sound pressure level difference D _j at frequency f _j in the following equation (4).
D _j = L _Aj −L _Bj (4)
In the calculation of the inter-room average sound pressure level difference D _j , the difference between the power averages L _Aij and L _Bij of the sound pressure levels in the sound source room A and the sound receiving room B is taken. The term relating to the number n of measurement points, which is the second term, is canceled out. Therefore, it may be omitted second term of the equation (3) in the calculation of L _Aij and L _Bij.
The measurement results are shown in a graph or table. In the case of the graph, the horizontal axis represents the frequency, the vertical axis represents the sound pressure level difference, and the sound pressure level for each center frequency is sequentially connected by a straight line.
When the difference between the maximum value and the minimum value of the sound pressure levels L _Aij (dB) and L _Bij (dB) at each measurement point in the sound source room A and the sound receiving room B is 5 dB or less, the calculation is performed. In order to save time and effort, the inter-room average sound pressure level difference may be approximated by an arithmetic average difference expressed by the following equation (5).
D _j = {(1 / n) · ΣL _Aij − (1 / n) · ΣL _Bij } (5)

However, the conventional method for measuring the inter-room sound pressure level difference is that the sound pressure levels L _Aij (dB) and L at the measurement points A _{1 to} A ₅ and the measurement points B _{1 to} B _{5 for} each center frequency f _{j. Since Bij} (dB) is measured one by one, not only about 30 minutes are required for the measurement in one room, but also about four workers are required as described above, and work efficiency is improved. There was a problem that it was extremely low. In particular, when the above measurement is performed in an apartment house, since there are many rooms, there is a problem that it takes a lot of time just to measure the sound insulation performance of the room. In addition, the calculation of the inter-room average sound pressure level difference D _j which is the final measurement result is 6 (frequency) × 5 (of each measured value L _Aij (dB) and L _Bij (dB) entered on the recording sheet after the measurement. Since the power average or the arithmetic average is obtained based on a total of 60 data of (measurement points) × 2, there is a problem that it takes time to calculate the measurement results.

  The present invention has been made in view of conventional problems, and a method for measuring an inter-room sound pressure level difference in which an average sound pressure level in a frequency band necessary for measurement can be obtained by a single measurement and its An object is to provide an apparatus.

The invention according to claim 1 of the present invention is a measurement of a sound pressure level difference between rooms, which measures a sound pressure level difference between a sound source room provided with a sound source and a room (sound receiving room) different from the sound source room. a method, Rutotomoni generates noise containing a plurality of frequencies to be used for the measurement of sound pressure levels in the sound source chamber, at different receiving room and the sound source chamber and the source chamber, the sound pressure signal of the noise The sound receiving means to be sampled is continuously moved along a predetermined route to collect the noise pressure signal of the noise, and the sound source signals of the sampled sound source chamber and the sound receiving chamber are collected for each of the plurality of frequencies. The band-limited sound pressure signal is extracted, the average value of the time change of the sound pressure signal for each frequency is calculated, and the inter-room sound pressure level difference for each frequency is calculated using the calculated average value. It is characterized by that.
Also, an invention according to claim 2, and the sound source device for generating noise in sound source chamber, the sound receiving means for collecting the sound pressure signals of the noise in different sound receiving chamber and the source chamber and the source chamber In the inter-room sound pressure level difference measuring device including the sound receiving device, the sound source device is a sound source device that generates noise including a plurality of frequencies used for sound pressure level measurement, and the sound receiving device. In addition, sound pressure data obtained by sampling a sound pressure signal obtained by continuously moving the sound receiving means along a predetermined route in a sound receiving chamber different from the sound source chamber and the sound source chamber at a predetermined sampling frequency. means for converting, the means for extracting the sound pressure data respectively band-limited for each of the plurality of frequencies from the sound pressure data, time variation or al the circumference of the sound pressure data for each frequency of the extracted In which characterized in that a means for calculating a chamber between the sound pressure level difference for each frequency by calculating the average value of the sound pressure data for each number.

According to the present invention, Rutotomoni generates noise containing a plurality of frequencies to be used for the measurement of sound pressure levels in the sound source chamber, at different receiving room and the sound source chamber and the source chamber, sound pressure signal of the noise the sound receiving means for each continuously moving at a predetermined route taken to collect sound pressure signal of the noise, bandwidth for each of the plurality of frequencies from the sound pressure signal of the sound source chamber and the receiving room, which is the harvested Extract the restricted sound pressure signal, calculate the average value of the time change of the sound pressure signal for each frequency, and calculate the inter-room sound pressure level difference for each frequency using this calculated average value since the, measured at a plurality of frequency bands required for measurement can be done in one measurement, Ru can significantly reduce the measurement time.

Hereinafter, the best mode of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a configuration and a measuring method of an inter-room sound pressure level difference measuring apparatus according to the best mode. The inter-room sound pressure level difference measuring apparatus is installed in a sound source room A. A sound source device 4 including a broadband noise generator 1 that generates noise including a plurality of frequencies used for pressure level measurement, a power amplifier 2, and a speaker 3, and the sound source room A and the sound source room A One microphone 5 that is a sound receiving means for collecting sound pressure signals in different sound receiving chambers B, a low noise amplifier 6 that amplifies the output of the microphone 5, and the output of the low noise amplifier 6 in the sound source chamber A And a sound receiving device 8 having a measurement unit 8A having a CPU 7 that calculates a mean value of sound pressure signals in the sound receiving chamber B and calculates an inter-room sound pressure level difference. Is done. In FIG. 1, the workers (S ₁ and S ₂ ) who perform the measurement are omitted.
As shown in FIG. 2A, the broadband noise generator 1 has six types of frequencies (f ₁ = 125 Hz, f ₂ = 250 Hz, f ₃ = 500 Hz, f ₄ = 1000 Hz, used for sound pressure measurement. _{f 5 = 2000Hz, f 6 =} 4000Hz) those which generate wideband noise containing, the noise is generally referred to as white noise, its output is flat with respect to frequency. In human hearing, even at the same sound pressure, the low frequency side seems to be small, so there is a case where the sound pressure level difference between rooms is measured using noise with a large output on the low frequency side. As shown in FIG. 2B, the device 1 can generate so-called pink noise with a large output on the low frequency side. In the best mode, the white noise is used as noise.
The CPU 7 of the sound receiving device 8 includes an A / D converter 9 for A / D converting the sound pressure signal input from the microphone 5 via the low noise amplifier 6 at a predetermined sampling frequency, and an A / D converter 9 for A For the sound pressure data in the sound source chamber A and the sound receiving chamber B stored in the RAM 10, and the RAM 10 storing the sound pressure signal (hereinafter referred to as sound pressure data) subjected to / D conversion, the above six frequencies are used. one of f ₁ ~f ₆ and a center frequency, a digital low-pass filter 11 to the upper limit of the octave band of the center frequency and the cutoff frequency f _c1, a cut-off frequency f _c2 the lower limit of the octave band of the center frequency a digital high-pass filter 12, to the digital low-pass filter 11 and the digital high-pass filter 12, a frequency setting means 13 for notifying the cutoff frequency f _c1, f _c2, the From band-limited sound pressure signal output from the digital high-pass filter 12, the average sound pressure level in the center frequency f ₀ in the or receiving room B source chamber _{A L Aj (dB), L} Bj (dB) Sound pressure level calculation means 14 for calculating the sound pressure level difference D _j (dB) for calculating the sound pressure level difference D _j (dB) for each frequency from the average sound pressure levels L _Aj (dB), L _Bj (dB) And means 15.

Next, a method for measuring the inter-room sound pressure level difference using the inter-room sound pressure level difference measuring apparatus of the best mode will be described. First, the apparatus is calibrated. This is to input a calibration signal built in the sound receiving device into the measuring unit 8A and check whether the maximum quantization value when A / D conversion is performed is a preset voltage value V _0. V ₀ is set as a reference value of the calibration sound pressure signal.
Next, the sound pressure level in the sound source room A is measured. In the sound source room A, the operator S ₁ operates the sound source device 4 to generate the above-described white noise (see FIG. 2A). The worker S ₂ moves the microphone 5 in the sound source room A continuously at a substantially constant speed for 10 to 30 seconds along a predetermined route as shown by a solid line in FIG. The sound pressure signal in A is sampled and sent to the measurement unit 8A, and the measurement unit 8A calculates the sound pressure level in the sound source chamber A by a sound pressure level calculation method described later. Then, the operator S _2, to move to the receiving room B, and the microphone 5, as indicated by a broken line in FIG. 1, at a preset predetermined route, moving 10 to 30 seconds continuously received sound The sound pressure signal in the room B is collected, and the sound pressure level in the sound receiving room B is calculated by the measuring unit 8A. The measuring unit 8A calculates the inter-room sound pressure level difference from the calculated sound pressure level in the sound source room A and the sound pressure level in the sound receiving room B. Measuring portion 8A of the sound receiving device 8, for example, be installed near the sound source device 4 in the source chamber A, it is assumed that the operator S ₁ is managed. When the sound pressure signal is collected, the sound source device 4 continues to generate white noise. Therefore, the operator S ₂ who collects the sound pressure signal operates the sound source device 4 and also measures the measurement unit of the sound receiving device 8. If the measurement unit 8A is operated by carrying the 8A or using a remote controller or the like, the sound pressure level can be measured by one worker.

Next, a method for calculating the sound pressure level from the sound pressure signal collected by the microphone 5 will be described in detail. Since the calculation method of the sound pressure level is the same in the sound source chamber A and the sound receiving chamber B, here, a case where the sound pressure level is calculated from the sound pressure signal collected in the sound receiving chamber B will be described. Note that the sound pressure signal collected by the microphone 5 in the sound source room A is subjected to a calculation process described later, and has already been converted into a sound pressure level, and then stored in the sound pressure level calculation means 14 (not shown). It shall be stored in the means.
Noise radiated from the speaker 3 in the sound source room A is collected in the sound receiving room B as a sound pressure signal by the microphone 5, amplified by the low noise amplifier 6 of the measuring unit 8A, and then A / D converter of the CPU 7. 9 is output. The A / D converter 9 samples the amplified sound pressure signal at a sampling frequency F _S0 = 44.1 kHz, for example, and converts it into digital data (sound pressure data) having a quantization bit number of 16 bits. The quantized sound pressure data is stored in the RAM 10. FIG. 3A is a diagram showing a time change of the sound pressure data, and FIG. 3B is a partially enlarged view thereof. As shown in FIG. 3A, the amplitude of the sound pressure data increases or decreases according to the position of the microphone 5 when the microphone 5 is continuously moved through the predetermined route in the sound receiving chamber B. . The quantized sound pressure data is a sound pressure signal including six types of frequencies (f _{1 to} f ₆ ) used for sound pressure measurement, as shown in FIG. .

4, from the sound pressure data stored in the RAM 10, a flow chart for calculating the average sound pressure level L _{j (j} = 1~6) for each of the six frequencies f ₁ ~f _6. First, the frequency setting means 13 sets the center frequency to f ₀ = 4 kHz (step S1), and the average sound pressure level L at f ₆ = 4 kHz from the sound pressure data in the sound receiving chamber B (see FIG. 3). _B6 is calculated. In this flowchart, the center frequency f ₀ is decreased by one octave, and the average sound pressure level L _B1 from f ₆ = 4 kHz to f ₁ = 125 Hz is sequentially calculated.
The frequency setting means 13 reads the quantized sound pressure data in the sound receiving chamber B from the RAM 10, sends it to the digital low-pass filter 11, and sets the cutoff frequency of the digital low-pass filter 11 to the center frequency f ₀ = 4 kHz. An instruction is given to set the upper limit value f _c1 of one octave band. The sampling frequency F _S of the digital low-pass filter 11 is 11.025 times the center frequency f ₀ , but when f ₀ = 4 kHz, the F _S is equal to the sampling frequency F _S0 in the A / D converter 9. Therefore, filtering is performed using all the sound pressure data (step S2). Next, the filtered sound pressure data is subjected to sampling frequency F _S filtering equal to F _S by the digital high-pass filter 12 whose lower limit of one octave band of the center frequency f ₀ is the cutoff frequency f _c2. from the sound pressure data, as shown in FIG. 5 (a), the center frequency f ₀ = extracts sound pressure data of the octave band 4 kHz (step S3). The extracted sound pressure data has a bandwidth of one octave, but in FIG. 5A, a simplified diagram is shown in which only the signal having the center frequency f ₀ is extracted.

Next, as shown in FIG. 6 (a), the band-limited sound pressure data is square-averaged and converted to the size of the sound pressure data, and then the converted sound pressure data is stored in advance. Averaging is performed every set time interval ΔT (for example, 1 second), and a sound pressure data size V _ij is obtained for each time interval ΔT (step S4). That is, as shown in FIG. 6 (b), the above-mentioned V _ij represents the positions obtained by dividing the moving route of the microphone 5 by time every ΔT as P ₁ , P ₂ ,..., P _i−1 , P _i ,. Corresponds to the average value of the sound pressure data in the section (P _i-1 -P _i ).
Therefore, the sound pressure level L _ij (dB) in the section (P _i-1 -P _i ) is the effective value V _C = V ₀ / √ of the above-described V _ij and the reference value V ₀ of the above-described calibration sound pressure signal. 2 and the sound pressure level L _C of the calibration sound pressure signal can be obtained by the calculation formula L _ij = 20 log ₁₀ (V _ij / V _C ) + L _C (step S5). Note that the above-mentioned square averaging is performed by squaring the data, and then correcting the square root after correction by applying a digital low-pass filter of the dynamic characteristic Fast in order to reflect the characteristics of the human ear against the temporal variation of sound. Thus, the quantization value corresponding to the sound pressure effective value is obtained.
The average sound pressure level L _{j at} the center frequency f _j (here j = 6) in the sound receiving chamber B is calculated from the following equation (6) using the above L _ij .
L _j = ₁₀ log ₁₀ (Σ10 ^{(Lij / 10)} ) (6)
In equation (6) is also section on the division number of the predetermined route, at the time of calculation of the level difference is omitted because it is canceled out, the sound pressure level above formula the value of (6) as the average sound pressure level L _j The data is stored in a storage means (not shown) provided in the calculation means 14.
When the measurement of the center frequency f _j sound average sound pressure level at L _j is completed, determining whether the center frequency f _j is a f ₁ = 125 Hz is the lowest frequency among the frequencies used in the sound pressure measurement (Step S7). Here, since the center frequency is f ₆ = 4 kHz, the frequency setting means 13 sets the center frequency f _j to f ₅ = 2 kHz which is (½) f _j and returns to step S 2 (step S 8). The average sound pressure level L _j at f ₅ = 2 kHz is calculated.
In this way, the average sound pressure level L _B1 from f ₆ = 4 kHz to f ₁ = 125 Hz is sequentially calculated by reducing the center frequency f ₀ by one octave. Therefore, when the center frequency f _j is f ₁ = 125 Hz in the above step S7, the average sound pressure level L _j at six types of frequencies used for sound pressure measurement is obtained. 4 is completed, and the inter-room sound pressure level difference is calculated.

Note that the data stored in the RAM 10 is not used again as quantized data (sound pressure data) used when calculating the average sound pressure level L _j at the center frequency (1/2) f _j. Data obtained by thinning out every other data filtered by the digital low-pass filter 11 obtained in step S2 is used. As a result, the number of data to be processed is reduced and the calculation time can be shortened. In addition, since the sampling frequency F _{S of} the digital low-pass filter 11 and the digital high-pass filter 12 is 11.025 times the center frequency f ₀ , the filtering may be performed using all the thinned data. FIG. 5B shows sound pressure data filtered and extracted by the digital low-pass filter 11 and the digital high-pass filter 12 when the center frequency f _j is f ₅ = 2 kHz, and is shown in FIG. Compared with the case of f ₆ = 4 kHz, since the sampling frequency F _S is ½ and the center frequency f ₀ is also ½, the number of samplings per wavelength is equal. Accordingly, the accuracy of the mean square at step S4 is not dependent on the center frequency f _0.

The room sound pressure level difference at each frequency f _j is calculated by the sound pressure level L _Aj (dB) of the sound source room A and the sound pressure level L _Bj of the sound receiving room B in the room sound pressure level difference calculating means 15. (DB) is read from a storage means (not shown) provided in the sound pressure level calculation means 14 and calculated by the following equation (7).
D _j = L _Aj −L _Bj (7)
Finally, this measurement result is represented by a graph in which the horizontal axis represents frequency, the vertical axis represents sound pressure level difference, and the sound pressure level for each center frequency is connected by a straight line in order to complete the measurement of the inter-room sound pressure level difference. . In the measurement method of the best mode, the time required for measurement is about 5 minutes including preparation.

As described above, according to the best mode, in the sound source room A, noise including a plurality of frequencies (f _{1 to} f ₆ ) used for measuring the sound pressure level using the broadband noise generator 1 of the sound source device 4. And a band-limited sound for each of the plurality of frequencies from sound pressure signals collected by moving the microphone 5 in the sound source room A and the sound receiving room B through predetermined routes for 10 to 30 seconds, respectively. A pressure signal is extracted, and an average sound pressure level L _Aj (dB) of the sound pressure signal for each frequency and an average sound pressure level L _Bj (dB) of the receiving chamber B are calculated from the extracted sound pressure signal. As a result, all frequency bands necessary for measurement can be performed in a single measurement, the measurement time can be greatly shortened and the number of workers can be reduced, greatly improving work efficiency. Can do.

In this best mode, the sound source device 4 including the broadband noise generator 1 that generates noise including a plurality of frequencies used for measurement of the sound pressure level is used, and the average at the plurality of frequencies is used. was measured Neon圧level L _j at the same time, using a conventional tone generator 24, since the move continuously and substantially constant speed at a preset given route a microphone 5, the measurement time Needless to say, it is possible to significantly reduce the time. In this case, since the bandwidth of the sound pressure signal collected by the microphone 5 is narrow, the configuration of the measuring unit 8A is simplified, such as simplifying the digital low-pass filter 11 and the digital high-pass filter 12 of the sound receiving device 8. It is possible to
Further, in the above example, the sound pressure signals in the sound source chamber A and the sound receiving chamber B are sampled so that the microphone 5 is continuously moved at a substantially constant speed along a predetermined route. Unless the room has a specific structure, the sound pressure level in the room does not change abruptly depending on the location, so that it is not necessary to move the microphone 5 strictly continuously and at substantially the same speed. In addition, if the time change of the sound pressure signal due to the movement of the microphone 5 is converted into the position change of the sound pressure signal by separately detecting the movement time and the moving speed of the microphone 5, the microphone 5 is not always continuous. It is not necessary to move at a constant speed.

By the way, the position average of the sound pressure signal, that is, the data of the sound pressure level L _ij (dB) in the section (P _i-1 −P _i ) described above is reference data for knowing the sound pressure distribution in the room. However, it is not necessarily data that must be obtained in order to calculate the inter-room sound pressure level difference. Therefore, the operation of setting the time interval ΔT and calculating the data of the sound pressure level L _ij (dB) in the section (P _i-1 −P _i ) described above is omitted, and the center frequency is expressed as follows. The average sound pressure level L _j at f _j may be obtained.
First, each quantized sound pressure data is square-rectified and then corrected by applying the above-described dynamic low-speed digital low-pass filter to obtain a square root of the corrected sound pressure data. The size of the sound pressure data is V _ij . Next, the sound pressure level L _ij (dB) of each data is obtained by the calculation formula L _ij = 20 log ₁₀ (V _ij / V _C ) + L _C , and the average sound pressure level L _j at the center frequency f _j is calculated as L _What is necessary is just to calculate from said Formula (6) using _ij . The sum (Σ) at this time represents the sum of all sound pressure data sampled at the sampling frequency corresponding to the center frequency f _j . Such data processing corresponds to the case where the time interval ΔT is set to a value equal to the sampling period of the digital low-pass filter 11 and the digital high-pass filter 12 in step S4 of FIG. 4 described above.

In the above example, the microphone 5 is used as one unit, and the sound pressures in the sound source room A and the sound receiving room B are collected. However, two microphones are used, and the measuring unit 8A is used in the sound source room A and the sound receiving room B. The two sound pressure signals can be processed independently. For example, if the configuration from the amplifier 6 and the A / D converter 9 to the sound pressure level calculation means 14 is a two-channel type having two series, the measurement time can be further shortened.
In the above best mode, unlike the prior art, since the sound pressure level can be calculated by the good power average precision, L _Aij (dB) and the difference between the maximum value and the minimum value of L _Bij (dB) is below 5dB The inter-room sound pressure level difference can be calculated without particularly distinguishing the cases.

  As described above, according to the present invention, measurement in a plurality of frequency bands necessary for measurement can be performed by one measurement, and the measurement time can be greatly shortened. The level difference can be measured efficiently.

It is a figure which shows the measuring method and measuring apparatus of the sound pressure level difference between rooms concerning the best form of this invention. It is a figure which shows the frequency distribution of the generated noise in this best form. It is a figure which shows the sound pressure signal after A / D conversion. It is a figure which shows the calculation method of the sound pressure level in this best form. It is a figure which shows the processing method of the sound pressure data in this best form. It is a figure which shows the processing method of the sound pressure data in this best form. It is a figure which shows the measuring method and measuring apparatus of the conventional inter-room sound pressure level difference. It is a figure which shows the frequency distribution of the conventional generated noise.

Explanation of symbols

1 Broadband noise generator, 2 Power amplifier, 3 Speaker, 4 Sound source device,
5 microphone, 6 low noise amplifier, 7 CPU, 8 sound receiving device, 8A measuring unit,
9 A / D converter, 10 RAM, 11 digital low pass filter,
12 digital high-pass filter, 13 frequency setting means, 14 sound pressure level calculation means, 15 sound pressure level difference calculation means.

Claims (2)

Rutotomoni generates noise containing a plurality of frequencies to be used for the measurement of sound pressure levels in the sound source chamber, at different receiving room and the sound source chamber and the source chamber, the sound receiving means for collecting the sound pressure signals of the noise The sound pressure signal of the noise is sampled by continuously moving each by a predetermined route, and the sound pressure is band-limited for each of the plurality of frequencies from the collected sound pressure signals of the sound source chamber and the sound receiving chamber. The signal is extracted, the average value of the time change of the sound pressure signal for each frequency is calculated, and the inter-room sound pressure level difference for each frequency is calculated using this calculated average value. Measuring method of sound pressure level difference between rooms. Inter-room sound pressure comprising a sound source device that generates noise in a sound source room, and a sound receiving device that has sound receiving means for collecting a sound pressure signal of the noise in a sound receiving room different from the sound source room and the sound source room In the level difference measuring device, the sound source device is a sound source device that generates noise including a plurality of frequencies used for measuring the sound pressure level, and the sound receiving device is different from the sound source chamber and the sound source chamber. in the receiving room, and means for converting the sound pressure data by sampling the sound pressure signals collected respectively is continuously moved at a predetermined route to the sound receiving means at a predetermined sampling frequency, from the sound pressure data means for extracting the sound pressure data has been band-limited, respectively for each of the plurality of frequencies, the mean value of the sound pressure data of the time change or we each frequency of the sound pressure data for each frequency of the extracted Calculated to measuring apparatus Interlaboratory sound pressure level difference, characterized in that a means for calculating a chamber between the sound pressure level difference for each frequency.

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